Liquid and air mixing gear pump

ABSTRACT

This invention relates to a two-gear pump for the formation of liquid and air emulsions, comprising a liquid intake at the point in which the gears begin to come out of mesh; a liquid and air mixture delivery port at the point in which said gears come into mesh, and an air intake port opening into the path of the crown of teeth of each gear outside their meshing point.

United States Patent [72] Inventor Poerio Carpigiani Via Cairoli l4,Bologna, Italy [21] Appl. No. 31,877 [22] Filed May 4, 1970 [45]Patented Dec. 21,1971 [32] Priority July 24, 1967; March 15, 1968 l 33Italy [31 I 7182A/67; 6884A/68 V Continuation of application Ser. No.747,300, July 24, 1968. This application May 4, 1970, Ser. No. 31,877

[54] LIQUID AND AIR MIXING GEAR PUMP 6 Claims, 7 Drawing Figs.

[52] US. Cl 417/310, 9 418/ I 5 [51] 1nt.Cl ..F04b 49/11, F04c 15/02[50] Field ofSearch 418/15; 417/310 [56] References Cited UNITED STATESPATENTS 1,804,604 5/1931 Gilbert 410/15 2,301,496 11/1942 Aldrich417/310 2,918,009 12/1959 Crevoisier 418/15 Hause et a1. CarpigianiMayes Cadman Cadman M0sbacher..

Adams Gustafsson Brush Vogt Cummins.... Kellett, Jr. Sivertsen HuberPrimary ExaminerWilliam L. Freeh Attorney-Imirie & Smiley ABSTRACT: Thisinvention relates to a two-gear pump for i 418/15 418/15 418/15 418/15418/15 103/126 103/126 103/126 103/40 103/7N 103/40 103/6X 103/7X 103/40PATENTEDUEBZHBYIIV 3, 29,893

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INVENTOR PoERio CARPIGI'AN! BY KM ATTORNEYS LIQUID AND AIR MIXING GEARPUMP This is a continuation of application Ser. No. 747,300 filed July24, 1968, now abandoned.

This invention relates to a two-gear pump for the feeding and mixing ofliquid and air for the formation of liquid and air emulsions by whichthe volume of air in the mix may be adjusted according to therequirements.

More particularly, the invention has for its object a two-gear pump ofthe aforementioned type, provided with adjustable means for thecontinuous or the stepwise adjustment of the reciprocal ratios of theliquid and gaseous phases of the liquidair emulsion being produced bythe pump in a given volume of emulsion delivered by the pump.

The above and other objects and advantages of the invention will beapparent from the following specification, made with reference to theaccompanying drawings, in which:

FIG. 1 shows in front view, with parts in vertical section, a firstembodiment of a gear pump according to the invention, adapted to formand deliver a mix of liquid and gas-usually air-and provided with meansfor the continuous adjustment of the air ratio in the mix.

FIG. 2 is a vertical section of the pump of FIG. 1.

FIG. 3 shows diagrammatically the development in a plane of theadjusting member of .the pump of FIGS. 1 and 2.

FIG. 4 is a front view of a second embodiment of pump according to theinvention.

FIG. 5 is a vertical section of the pump of FIG. 4, on line V-V of FIG.4.

FIG. 6 is a vertical section of the same pump, on line Vl-VI of FIG. 4.V

FIG. 7 is a bottom plan of the pump shown in FIG. 4.

FIG. 8 shows diagrammatically the development in a plane of the sectionadjusting member of the pump of FIGS. 4 to 7.

With reference to FIGS. 1 and 2 of the drawings, the gear pump showncomprises a hollow casing section 1, tightly closed by a cover 2fastened to the casing 1 by means of suitable bolts 3. A suitable O-ring4 housed inside a groove formed into the peripheral edge of the casing lassures a fluidtight seal between casing 1 and cover 2.

Inside casing 1 two cylindrical chambers 5 are formed, crossing eachother along the pump central vertical plane. Inside said chambers 5 apair of gears 6, 106 in mesh with one another are housed.

The gear 6 is keyed onto shaft 7, projecting outwardly of casing 1through a suitable bore. An O-ring 8 is mounted in a groove inside saidbore, so as to provide for a tight seal between shaft 7 and the borewalls.

Cover 2 is formed at its middle area with a boxlike extension 202, inwhich a cylindrical chamber 9 is bored. Chamber 9 communicates at oneend through port 109 with the pump delivery duct 10. The other end ofchamber 9 is closed by means of the cylindrical plug 13. The plug 13 isprovided with a circumferential groove housing an O-ring 213, for atight seal with the wall of chamber 9. The plug 13 is provided with anaxial through bore 313, opening at one end inside of chamber 9, while atits opposite end is connected to one end of the liquid mix suction pipe413. The plug 13 is provided at its end projecting inside of chamber 9with a hollow cylindrical sleeve or collar 15, having a substantiallyhelical profile, facing the liquid suction port 14, as best shown inFIG. 3. A double-acting valve 11 is slidably mounted inside chamber 9,and is constantly urged upwardly, against port 109, by a spring 12abutting against the bottom of plug 13.

Plug 13 is furthermore provided with an external abutment flange 113,and with a radially projecting operating lever 216.

Two air inlet ports 16, 116 formed in the pump casing, are communicatingeach with the suction side of the gears 6, 106.

The operation of the just-described pump is as follows: when the gears6, 106 rotate, the pump sucks the liquid from pipe 413 through the port14, and mix it with the air sucked through the ports 16 and 116, theamount of air sucked by the gears being proportional to the amount ofliquid filling the space between the gears. As a consequence, byreducing the amount of liquid, an air-richer emulsion will beautomatically produced, and vice versa.

This is accomplished according to the invention by angularly adjustingthe sleeve or collar 15 with respect to the port 14, by simply rotatingthe plug 13. In this manner, as best shown in FIG. 3, it is possible tocontinuously pass from one position (position I) of port 14 and collar15 in which port 14 is fully uncovered, to a position in which port 15is fully covered (position [11) through intermediate air/liquidadjustment positions in which the gear pump will suck amounts of liquidwhich are proportional to the uncovered area of slot 14, the remainingof the volume (that is a volume which is proportional to the coveredportion of port 14) being provided by the air sucked by the gears 6, 106through the apertures 16, 116.

The air and liquid phases sucked by the pump are thereafter emulsifiedin a conventional manner by the gears, and are thereafter pumped throughthe delivery port 10.

The valve 11 is a bypass valve, which pennits to the emulsified mixtureto be returned from the delivery 10 to the pump suction side, any timethe pressure at the delivery side goes up over a predetermined value. Asshown, valve 11 is provided with a lower extension 111, for closing theport 313 whenever valve 11 opens, so as to avoid that the bypassedemulsion be returned through duct 413 to the liquid mix tank.

In FIGS. 4 to 8 a second embodiment of the gear pump according to theinvention is shown, for the stepwise adjustment of the air-liquidratios. The pump shown in the said figures is substantially the same asthe pump previously described. The main difference resides in the factthat the plug 13 is provided with a cylindrical collar or sleeve 215which, as best shown in FIG. 8, is provided with a set of calibratedports F1...F7, of increasing diameter. By putting one of the said portsinto alignment with the suction port 14 of the gear pump inlet, thedesired air-liquid ratio is obtained. For the exact alignment of theports F1...F7 with the port 14, The plug 13 has an external flange 513,provided with a number of notches 613 corresponding to the number ofcalibrated ports F1...F7 and coacting with abutment member 713.

As best shown in FIG. 5, the bypass valve in the embodiment as showncomprises a valve body 111, for the closure of port 109. A stem 211 offlexible material extends downwardly from the lower side of said valve111., bearing at its free end a ball valve 311. The valve 311 isnormally held at a certain distance from port 313. Whenever valve 111opens, valve 311 is lowered onto port 313, thus closing said port andavoiding any return of liquid down pipe 413 into the mix tank.

The operation of the pump shown in FIGS. 4 to 8 is the same as theoperation of the pump of the previous embodiment, with the onlydifference that the adjustment is stepwise.

Although the gear pum'p described and shown was mainly devised for useon soft ice cream-making machines and expresso whipped cream-makingmachines, it will be understood that same may be usefully employedwhenever a liquid and gas emulsion is desired.

Having thus described my invention, what I claim is:

1. A mixing pump having an output which is an admixture of anincompressible and a compressible fluid successively supplied in aclosely controlled proportion comprising a casing having separate inletsfor said fluids and at an outlet for said admixture,

interrneshing rotor means in said casing having at least one recess ofpredetermined volumetric capacity to receive said fluids, said inletsand outlet being connected to said rotors,

said incompressible fluid being received in said recess at a point wheresaid rotors move out of mesh said compressible fluid being received insaid recess at a point between said inlet and said outlet and beingmixed with said incompressible fluid during passage to said outlet, and

means for controlling the volume of flow of said incompressible fluid tosaid rotors whereby the proportion of the admixture components isclosely controlled, said means comprising a chamber connecting saidincompressible fluid inlet with said rotors, and valve means for saidchamber for controlling the flow of said fluid to said rotors,

said chamber having a port leading to said outlet and said valve meanscomprising a double-acting valve controlling the flow to said rotors andback flow from said outlet.

2. A mixing pump having an output which is an admixture of anincompressible and a compressible fluid successively supplied in aclosely controlled proportion comprising a casing having separate inletsfor said fluids and an outlet for said admixture,

intermeshing rotor means in said casing have at least one recess ofpredetermined volumetric capacity to receive said fluids, said inletsand outlet being connected to said rotors,

said incompressible fluid being received in said recess at a point wheresaid rotors move out of mesh said compressible fluid being received insaid recess at a point between said inlet and said outlet and beingmixed with said incompressible fluid during passage to said outlet, and

means for controlling the volume of flow of said incompressible fluid tosaid rotors whereby the proportion of the admixture components isclosely controlled, said means comprising a chamber connecting saidincompressible fluid inlet with said rotors, and valve means for saidchamber for controlling the flow of said fluid to said rotors,

said chamber having a port connected with said outlet, a

sleeve within said chamber, a second valve member normally closing saidlast named port, and resilient means seated on said sleeve and urgingsaid second valve member towards the closed position.

3. A liquid and air mixing gear pump comprising a pump casing,

a pair of intermeshing gears rotatably mounted inside said casing,

a liquid intake duct ending with a port at a point in which said gearsbegin to come out of mesh;

means comprising an adjustable shutter for varying the free flow passagearea of said liquid intake port,

a liquid and air mixture delivery port at the point in which said gearscome into mesh, and

an air intake port opening in the path of the crown of the teeth of eachgear between said liquid intake and said liquid and air mixture deliveryport.

4, A pump according to claim 3 in which said shutter is provided with anumber of calibrated ports individually movable into the area of saidliquid intake port.

5. A pump according to claim 3 further comprising a bypass valveconnecting the said delivery port with said liquid intake port,

6. A mixing gear pump having an output which is an admixture of a liquidand air successively supplied in a closely controlled proportion,comprising a pump casing,

a pair of intermeshing gears rotatably mounted in said casa liquidintake duct ending with a port at a point in which said gears begin tomove out of mesh,

means for varying the free flow passage area of said liquid intake duct,

a liquid and air mixture delivery port at the position where the saidgears move into mesh,

and for each gear an air intake port disposed to supply air to the teethof the gear at a position between said liquid intake and said liquid andair mixture delivery port.

F i 1i 10K

1. A mixing pump having an output which is an admixture of anincompressible and a compressible fluid successively supplied in aclosely controlled proportion comprising a casing having separate inletsfor said fluids and at an outlet for said admixture, intermeshing rotormeans in said casing having at least one recess of predeterminedvolumetric capacity to receive said fluids, said inlets and outlet beingconnected to said rotors, said incompressible fluid being received insaid recess at a point where said rotors move out of mesh saidcompressible fluid being received in said recess at a point between saidinlet and said outlet and being mixed with said incompressible fluidduring passage to said outlet, and means for controlling the volume offlow of said incompressible fluid to said rotors whereby the proportionof the admixture components is closely controlled, said means comprisinga chamber connecting said incompressible fluid inlet with said rotors,and valve means for said chamber for controlling the flow of said fluidto said rotors, said chamber having a port leading to said outlet andsaid valve means comprising a double-acting valve controlling the flowto said rotors and back flow from said outlet.
 2. A mixing pump havingan output which is an admixture of an incompressible and a compressiblefluid successively supplied in a closely controlled proportioncomprising a casing having separate inlets for said fluids and an outletfor said admixture, intermeshing rotor means in said casing have atleast one recess of predetermined volumetric capacity to receive saidfluids, said inlets and outlet being connected to said rotors, saidincompressible fluid being received in said recess at a point where saidrotors move out of mesh said compressible fluid being received in saidrecess at a point between said inlet and said outlet and being mixedwith said incompressible fluid during passage to said outlet, and meansfor controlling the volume of flow of said incompressible fluid to saidrotors whereby the proportion of the admixture components is closelycontrolled, said means comprising a chamber connecting saidincompressible fluid inlet with said rotors, and valve means for saidchamber for controlling the flow of said fluid to said rotors, saidchamber having a port connected with said outlet, a sleeve within saidchamber, a second valve member normally closing said last named port,and resilient means seated on said sleeve and urging said second valvemember towards the closed position.
 3. A liquid and air mixing gear pumpcomprising a pump casing, a pair of intermeshing gears rotatably mountedinside said casing, a liquid intake duct ending with a port at a pointin which said gears begin to come out of mesh; means comprising anadjustable shutter for varying the free flow passage area of said liquidintake port, a liquid and air mixture delivery port at the point inwhich said gears come into mesh, and an air intake port opening in thepath of the crown of the teeth of each gear between said liquid intakeand said liquid and air mixture delivery port.
 4. A pump according toclaim 3 in which said shutter is provided with a number of calibratedports individually mOvable into the area of said liquid intake port. 5.A pump according to claim 3 further comprising a bypass valve connectingthe said delivery port with said liquid intake port.
 6. A mixing gearpump having an output which is an admixture of a liquid and airsuccessively supplied in a closely controlled proportion, comprising apump casing, a pair of intermeshing gears rotatably mounted in saidcasing, a liquid intake duct ending with a port at a point in which saidgears begin to move out of mesh, means for varying the free flow passagearea of said liquid intake duct, a liquid and air mixture delivery portat the position where the said gears move into mesh, and for each gearan air intake port disposed to supply air to the teeth of the gear at aposition between said liquid intake and said liquid and air mixturedelivery port.